OFFSET
0,3
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 0..693
N. Heninger, E. M. Rains and N. J. A. Sloane, On the Integrality of n-th Roots of Generating Functions, J. Combinatorial Theory, Series A, 113 (2006), 1732-1745.
MATHEMATICA
terms = 17; QP = QPochhammer; s = ((QP[q]^18*(4 - 4*(1 + (9*q*QP[q^9]^3) / QP[q]^3)^3 + 3*(1 + (9*q*QP[q^9]^3)/QP[q]^3)^6))/(3*QP[q^3]^6))^(1/6) + O[q]^terms; CoefficientList[s, q] (* Jean-François Alcover, Jul 08 2017, after Michael Somos *)
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane and Michael Somos, Jun 07 2005
STATUS
approved